1. Field of the Invention
The present invention relates to a clip and a curtain airbag mounting structure and a pillar garnish mounting structure using the same. Hereinafter, the curtain airbag is also referred to as “CSA”. The CSA is an abbreviation of the curtain shield airbag.
2. Description of Related Art
Japanese Patent Application Publication No. 2010-144830 (JP 2010-144830 A) has disclosed a clip of lock pin type for mounting the CSA on a vehicle body, for example, an inner panel of a front pillar (referred to as A pillar also). This clip has a clip main body and a lock pin. The clip main body includes a seating portion, a single leg portion which extends in a direction in which they leave the seating portion and is to be inserted into a clip mounting hole in the body, and a pair of locking pawls which are arranged in an opening portion provided on both sides of the leg portion. The pair of the locking pawls extend toward the seating portion from a connecting portion with the leg portion which is located far from the seating portion. The external side face of the locking pawl is inclined along a direction in which they approach a clip central axial line as it leaves the seating portion far.
At the time of inflation of the CSA, a tensile load which pulls the clip obliquely is applied by the CSA. Of this oblique tensile load, a load component in the clip axis direction is borne by the clip axial direction shearing strength of the locking pawl and a load component in a direction perpendicular to the clip axial direction is borne by the shearing strength in a direction perpendicular to the clip axial direction of the leg portion.
However, the clip as disclosed in JP 2010-144830 A in which the locking pawl extends toward the seating portion has a following problem.
For the leg portion and the locking pawl to be able to pass through the clip mounting hole in the body at the time of clip mounting, a projection amount of the locking pawl from an external side face of the leg portion cannot be set large. Thus, a locking allowance of the locking pawl to a clip mounting hole edge portion after passing the clip mounting hole cannot be secured to be large enough. For the reason, if it is requested to increase the clip axial direction strength of the locking pawl, it is sometimes difficult to satisfy such a demand. Further, because the looking pawls are provided in an opening portion of the leg portion and the width of the locking pawl is smaller than the width of the leg portion, if there is a demand for increasing the clip axial direction strength of the locking pawl further, it is sometimes difficult to satisfy such a demand. Further, if the width of the locking pawl is made too large, it comes that the width of the leg portion becomes small, which may lead to breaking of the leg portion.
Further, because an opening portion in which the locking pawl is to be arranged is provided on both sides of the leg portion, the sectional area in a direction at right angle to the axis of the leg portion is smaller compared to a sectional area when the inside of the external shape of the leg portion is substantially filled and the shearing strength in the direction at right angle of the leg portion is small. Thus, even if it is intended to increase the strength in the direction at right angle to the axis of the leg portion further, such a demand sometimes cannot be satisfied.
Additionally, Japanese Patent Application Publication No. 2007-098986 (JP 2007-098986 A) has disclosed a tether clip in which a pillar garnish that accommodates the CSA is mounted on an A pillar and scattering of the pillar garnish at the time of inflation of a CSA is prevented.
FIGS. 22 to 25 show a comparative example clip (hereinafter also referred to as comparative clip) 111 which was considered on the halfway of development of the present invention. As shown in FIGS. 22 to 25, the comparative clip 111 containing the clip according to Japanese Patent Application Publication No. 2013-180725 (JP 2013-180725 A) has a pair of locking pawls 131 opposed to each other and opposing internal side faces 135 of the pair of the locking pawls 131 are flat.
However, when the pair of the locking pawls 131 are mounted in the body clip mounting hole or removed from the clip mounting hole at a service time, the comparative clip 111 receives a restriction due to interference between the opposing internal side faces 135 and a restriction due to insertion into the clip mounting hole, so that a following problem occurs.
(a) Because no sufficient thickness in a deflection direction of the locking pawl 131 can be secured, stiffness in the deflection direction of the locking pawl 131 sometimes cannot be secured. In this case, if a load in the clip axial direction is applied to the locking pawl 131 at the time of inflation of the CSA, the locking pawl 131 is deformed as shown with two-dot dash line of FIG. 25, so that there is a fear that the clip 111 may slip out of the clip mounting hole 193 in the body 191 so that scattering of a pillar garnish cannot be prevented. (b) If the thickness of the locking pawl 131 is increased to secure stiffness in the deflection direction of the locking pawl 131, engagement allowance of an edge portion of the clip mounting hole with a pawl decreases. (c) If the thickness of the locking pawl 131 is increased to secure stiffness and the engagement allowance of the locking pawl 131 is also secured, interference occurs between the opposing internal side faces 135 of the pair of the locking pawls 131 upon insertion of a tether clip 111 into the clip mounting hole 193 or removal thereof. As a result, not only a trouble occurs in insertion into the clip mounting hole, but also sink marks occur at molding time due to the increased thickness.